Methodology for Evaluating the Performance of Bituminous Binders Based on Rheological Indicators: Impact of the Use of a Rejuvenator

Abstract

In order to increase further the recycling rates of reclaimed asphalt (RA) while maintaining performance, road contractors use more and more additives called rejuvenators. The desired effects include a regeneration of the aged RA binder properties and an improvement of the asphalt mixture performance containing a high RA content. At present, no standardized procedure applicable to a bituminous binder exists to evaluate the impact of different commercial rejuvenators. Therefore, within the framework of the Re-RACE (Rejuvenation of Reclaimed Asphalt in a Circular Economy) research project, the Belgian Road Research Centre aims to develop a screening procedure in order to evaluate the effectiveness of additives to rejuvenate bituminous binders from rheological indicators. To establish an appropriate selection, each indicator is evaluated on its representativity in terms of asphalt mixture performance (cracking, rutting …), on its precision, on its sensitivity to ageing and on its potential correlations with the other indicators. To support this study, rheological measurements were performed on a 50/70 grade bitumen at different ageing stages and two bituminous blends of fresh and long-term aged bitumen with or without rejuvenator corresponding to 70% RA. This article presents the results related to rheological indicators evaluating the risk of cracking at intermediate temperature. This investigation is part of a broader methodology to assess the performance of bituminous binders and will provide in the future a screening procedure for evaluating the effect of rejuvenators while using high RA rates.